Size dependence of the thermo-electrodynamics states of composite high-Tc superconductors and its effect on the current instability conditions

The effect of transverse geometries of the slab of composite high-T_c superconductors on their stable and unstable thermal and electrodynamics transient states in the incomplete and complete penetration modes during the current charging are discussed. The transient period when the electric field that is induced by the charged current becomes more homogeneous during the initial stage of the complete penetration mode in the sub-critical voltage range is studied. In the over-critical voltage range, the cross-section shape of the slab affects its stable and unstable temperature variation. As a result, the current instability condition is not identical for high-T_c superconducting composite tapes that have the same cross-sectional area with various shapes of the cross-section. The condition depends on their thickness: the less thickness, the more stable the current distribution in the composite superconductors with the same cross-sectional area. This feature is a result of the unavoidable reduction of the current-carrying capacity of a high-T_c superconducting composite by the temperature increase. This reduction is caused by the relevant temperature dependence of electrodynamics states of the composite. This temperature dependence happens even during a stable stage of the current charging. These mechanisms must be considered during experiments at which the critical or quenching currents are defined.     

Evaluation of firm’s loss due to incomplete information in real investment decision

We investigate the effect of incomplete information in a model where a start-up with a unique idea and technology pioneers a new market but will eventually be expelled from the market by a large firm’s subsequent entry. We evaluate the start-up’s loss due to incomplete information about the large firm’s behavior. We clarify conditions under which the start-up needs more information about the large firm. The proposed method of evaluating the loss due to incomplete information could also be applied to other real options models involving incomplete information.     

A stochastic system with MMPP input and an access function

In classical studies of loss systems with restricted availability, the utilization was suggested of a probabilistic loss function, defining the conditional probability of an incoming call being rejected, as a function of the number of occupations in the destination group of servers. This paper gives an exact analysis of stochastic processes of practical relevance, associated with a system with MMPP (Markov Modulated Poisson Process) input, finite queueing capacity and a general loss function, assuming exponential service times. In addition to the process defining the state of the system at any instant, the analysis of the overflow point process (associated with the rejected arriving customers), the accepted point process (associated with the accepted arriving customers), and of the departure process will be presented. Together with the exact analysis of this system, based on the matrix analytical methodology of Neuts, (1981), we will derive expressions for calculating some key-parameters of pertinent associated processes, which may also be used for their approximate modelling. Also, examples of applications and of blocking probability calculations in specific models of this class will be presented.     

High Power THz Undulator Radiation from Linear Accelerator

A 30-MeV femto-second electron linac is built at the Shanghai Institute of Applied Physics, which can produce high power, coherent THz undulator radiation. We report the experimental facility and measurement of the power, frequency spectrum. First experiments show the averaged power at THz to be about 20mW.     

Design of organic 3D microresonators with microfluidics coupled to thin-film processes for photonic applications

We report on the design and realization of photonic integrated devices based on 3D organic microresonators (MR) shaped by an applied fluid mechanism technique. Such an interdisciplinary approach has been judiciously achieved by combining microfluidics techniques and thin-film processes, respectively, for the realizations of microfluidic and optical chips. The microfluidic framework with flow rates control allows the fabrication of microresonators with diameters ranging from 30 to 160 μm. The resonance of an isolated sphere in air has been demonstrated by way of a modified Raman spectroscopy devoted to the excitation of Whispering Gallery Modes (WGM). Then the 3D-MR have been integrated onto an organic chip and positioned either close to the extremity of a taper or alongside a rib waveguide. Both devices have proved efficient evanescent coupling mechanisms leading to the excitation of the WGM confined at the surface of the organic 3D-MR. Finally, a band-stop filter has been used to detect the resonance spectra of organic resonators once being integrated. Such spectral resonances have been observed with an integrated configuration and characterized with a Δλ = 1.4 nm free spectral range (FSR), appearing as stemming from a 78 μm-radius MR structure.     

Repeated newsvendor game with transshipments under dual allocations

We study a repeated newsvendor game with transshipments. In every period n retailers face a stochastic demand for an identical product and independently place their inventory orders before demand realization. After observing the actual demand, each retailer decides how much of her leftover inventory or unsatisfied demand she wants to share with the other retailers. Residual inventories are then transshipped in order to meet residual demands, and dual allocations are used to distribute residual profit. Unsold inventories are salvaged at the end of the period. While in a single-shot game retailers in an equilibrium withhold their residuals, we show that it is a subgame-perfect Nash equilibrium for the retailers to share all of the residuals when the discount factor is large enough and the game is repeated infinitely many times. We also study asymptotic behavior of the retailers’ order quantities and discount factors when n is large. Finally, we provide conditions under which a system-optimal solution can be achieved in a game with n retailers, and develop a contract for achieving a system-optimal outcome when these conditions are not satisfied.     

The selection efficiency of tournaments

We discuss tournaments in terms of their efficiency as probabilistic mechanisms that select high-quality alternatives (“players”) in a noisy environment. We characterize the selection efficiency of three such mechanisms – contests, binary elimination tournaments, and round-robin tournaments – depending on the shape of the distribution of players’ quality, the number of players, and noise level. The results have implications as to how, and under what circumstances, the efficiency of tournament-based selection can be manipulated.     

Semiclassical method for calculating the energetic values of helium, lithium and beryllium atoms

In previous papers we have presented a wave model for conservative bound systems resulted from the equivalency between the Schrödinger and wave equations. We proved that the normal curves of the characteristic surface of the wave equation, denoted by C curves, are solutions of the Hamilton-Jacobi equation, written for the same system, and correspond to the same constants of motion as those resulting from the Schrödinger equation. In this paper we present a method for computing the energetic values of conservative bound systems which is based on the properties of the C curves. The method is applied to the 1s ² state of helium, 1s ²2s and 1s ²2p states of lithium and 1s ²2s ² state of beryllium. Our theoretical values are compared with experimental data taken from well-known books. The relative error of our method is less than 5 x 10^?3.     

一种被动式单波长实时测温系统的优化设计

基于Kirchhoff定律,利用一面反射镜,设计了一种可同时测量发射率及温度的单波长实时测温系统.从系统的测温灵敏度、相对测温灵敏度、探测器的温度分辨力及系统的测温标准差与波长的关系出发,并结合大气对红外辐射的透射特性,优化了系统的工作波长; 从系统的抗反射辐射能力与波长带宽的关系出发,并结合探测器的最小可探测光功率要求,优化了系统的波长带宽.实验结果表明,当λ=0.80 μm、Δλ=20 nm时,在测温范围600~2 500℃内,系统的测温不确定度优于0.3%.     

The maximum multiplicity of the largest k-th eigenvalue in a matrix whose graph is acyclic or unicyclic

Given a graph $G$ we are interested in studying the symmetric matrices associated to $G$ with a fixed number of negative eigenvalues. For this class of matrices we focus on the maximum possible nullity. For trees this parameter has already been studied and plenty of applications are known. In this work we derive a formula for the maximum nullity and completely describe its behavior as a function of the number of negative eigenvalues. In addition, we also carefully describe the matrices associated with trees that attain this maximum nullity. The analysis is then extended to the more general class of unicyclic graphs. Further our work is applied to re-describing all possible partial inertias associated with trees, and is employed to study an instance of the inverse eigenvalue problem for certain trees.